Let’s be honest: after a busy week, it’s tempting to toss towels and clothes into the same load and hit “Start.” But that innocent shortcut often backfires. While combining them might seem efficient, it can actually wear out your items faster, dull your favorite clothes, and even spread unexpected germs.

I used to do it, too—until I began noticing lint-covered tees, stiff towels, and clothes that just didn’t feel right after washing. That’s when I dug deeper and discovered there’s big laundry logic behind separating towels from clothing. Here’s what I learned.